contemporaneous

Concise Oxford English Dictionary © 2008 Oxford University Press:
contemporaneous /kənˌtɛmpəˈreɪnɪəs, kɒn-/

▶adjective existing at or occurring in the same period of time.

– derivatives
contemporaneity /-ˈniːɪti, -ˈneɪɪti/ noun,
contemporaneously adverb,
contemporaneousness noun.

– origin C17: from L., from con- ‘together with’ + temporaneus (from tempus, tempor- ‘time’) + -ous.